Rubber composition and method of preserving rubber



r Patented Feb. 24, 1931 no nmwin j MARION c. REED; onoUYAHoGA FA smHIo, Assxeiwon TO THE B. r. GOQDRICH. COIVI- PANY, OE NEW Yo 1?. K, N. Y,.',' A conronarron or NEW YORK 1 r mmmrc'omc mqr AnD'ivrETHo-n or' rmismwrne omania- I Thisinvention "relates to the art of preserving rubber, either in the vulcamzed-or positions so preserved.

It is well known that rubber, is. subject to more or less rapid deterioration uponaging, especially when exposed to light, he'at,or a1-r. It has been proposed to treat rubber with so-call-ed anti-oxidants for the purpose of r pounds, aromatic amino compounds, and'the condensation products of aldehydes and amines. I Y 7 This lnventlon consists in treatlng rubber with a member of a new class of extremely effective anti-oxidants.

This class'includes the asymmetrical diaryl hydrazines of the general structural formula radical. For example, the class includes asymmetrical diphenyl hydrazine, ditolyl hydrazine, dixylyl hydrazine, di-biphenyl hydrazine, dinaphthyl hydrazine, phenyl tolyl hydrazine, phenyl biphenyl hydrazine,

phenyl naphthyl hydrazine, tolyl naphthyl hydrazine, etc. These compounds may be prepared by any convenient method, such as by the reduction or the corresponding nitrosamine.

Rubber or rubber compositions may be rendered extremely resistant to deterioration by incorporating therein a small proportion of one of the above-mentioned asymmetrical "diaryl hydrazines, preferably in the proportion of from 1/10 to 5 parts by Weight being added to each 100 parts of rubber. Rubber so treated withstands oxidation or exposure to sunlight or'the elements for a far longer period than similar untreated rubber, with-.

out sensible deterioration. 7

EwampZe 1.-As a specific example of one embodiment of the method of this invention,

a typical tire tread composition Was prepared containing: blended plantation rubber 100 unvulcanized condition, and to rubberboma aii ncafi mfi a a rii 5, 1930.- Ja et No. 442mm. 7

two portions, one fo'fjWh-ich: was; used as a controhfivhile the other was mixed with 1.9

,tetr.amine 0.75 parts. "This was divided into,

parts of asymmetrical diph'enylhydrazine (1% or the eight of the composition). The composition Was thoroughlyimlixed, and Vul- (290; F.) topreduce an' optimum cure. The

.relative'rates ofaging of theVuIcanized-'con11-' positions were compared by measuring-- their respective tensile strengths {and elongations before and after aging; Acceleratedaging testswere carried out in the Geer aging oven,

in whichisamples were maintained at afternperaturelbi'TSJKC. (158? in a' constantly renewed stream of 7 air. 7

151111 the tablebelow Tjindicates ultimate tensile strength in: pounds per square inch cent of original length.j

Agingtests of dipheng L hydraz-ine- Ewample 2A rubber composition waspreexcept-that'the diphenyl hydrazine was purified by distillation before it was used. The vulcanized rubber was tested before and after aging in the Geer oven and in the Bierer- .Davi's:.bomb,-in Whichthe samples w'ere maintainedat. thesametemperature (70C.) in an atmosphere o f'oxygen' at a pressure of 800 lbs. persq: in.- Tnnumerous tests the composition Without thedipheny'l' hydrazine deteriorates to such an extent thatits-tensile strength a-fteni LS hours in the Bierer-Da vis and E indicates ultimate elongation inper pared similar to that of Example l above 1. The method bomb is less than 1000 pounds per: square inch.

Aging tests of purified diphenyl hydrazine Before g z l y ili i iii f r aging e ierer- Antioxidant Geer W Davis bomb T712 '1 air it drazine From these enamples is evidentthat the asymmetrical diaryl hydrazinesare extreme- .ly effective in retarding the deleterious action normallyincident to the aging-of rubber.

Obviously, the practice ofthisinvention is not limited to the specific compositions give11 above, suchjeompositions being merely illustratlve of one manner of employingthe anti-oxidants of this invention. The pro portions of the constituents may be varied, or other substances may be substituted therefor, since this invention is applicable topure rubberor rubber compositions of the most varied nature. 7 Other accelerators such as aldehydeamin'e reaction I products, diphenyl comprises treating rubberWith asymmetrical diaryl hydrazine.

2. The method of preserving rubber which comprises treating rubber with asymmetrical diaryl hydrazine.

. 3. .The method of preserving rubber which comprises vulcanizing rubber in the presence of'an asymmetrical diaryl hydrazine.

4. The method of preserving rubber which comprisesvulcanizing. rubberi'in. the presence of-asymmetricaldiphenyl hydrazine.

5. A composition of matter comprising rubi ber and an asymmetrical diaryl hydrazine.

6. A composition of matter comprising rub:

. her and asymmetrical diphenyl hydrazine." 7.; A, composition ofmatter comprising rubber vulcanized in the presence of an a 'sy n metrical diaryl hydrazine;

. 8. A composition of matter comprising cal diphenyl hydrazine. g slnwitness hereofI have hereunto set my hand this 31st day of March, 1930. w

. M ARI OlSI G. REED.

ber vu'lcanized in the presence of asymmetri guanidin'e, di ortho tolyl thiourea, mercapto I benzothiazol, 'tetramethyl thiuram monosulphide, etdmay be substituted for the hexamethylene tetramine 'of the examples above, although better results will be secured with some accelerators tha-nwith others." The anti-oxidants may also be applied to unvulcani'zed or vulcanized rubber with good ef feet on the ageresisting properties of the rubber, such as by'applying them to the sur; face of the rubber, as for example in solution, or in the form of a paste or emulsion.

Itis to be understoodthatthetermtreating I do notthereby desire or intend to limit myg self solely thereto, for, as hitherto stated, the precise proportions of the materials utilized maybe varied andother materials having.

equivalent chemical properties. may .be employed if desired Without departing from the T spirit and. scope. of the invention as defined.

in the appended claims.

:Iclaim: l of preserving rubber wh ch rot CERTIFICATE 6F CORRECTIGN.

Fateht Ne. 1,793,635. Grantad February 24, 1931, to

MARIGN G. REED.

It is hereby certified that error app-sars in the printed specification of the above numbered patent requiring correciion as fail-0W3: Page 1, line 68, for "79 i3." read 70 (1.; page 2-, line 70,- hiaim 2, im' "diary! hydrazine" read diphenyi hydrazine; and ihat the said Leiters Fatant shmzld be read with these ccrrectisns therein that the same may carriers: to the record of the case in the Patent @fiica.

Signed ami seaied this 22nd day of Septembsr, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents, 

